1. Field of Invention
The present invention relates to an apparatus for keeping a needle aligned under an ultrasound beam and, more particularly, for guiding a needle used for administering anesthetic.
2. Prior Art to Invention
Ultrasound systems for real time visual guidance of a needle into a patient""s body are known and have been utilized for biopsies, drainage of fluids, amniocentesis, and the like. Generally, the physician uses one hand to hold the transducer against the body of the patient to visualize the target, and the other hand to guide the needle into the patient and hit the target. The ultrasound beam is planar in nature and visualizes the target and the needle as it comes close to the target.
In order to steady the relative position of the transducer, the ultrasound beam, and the needle, various apparatuses have been suggested, see U.S. Pat. Nos. 4,899,756; 5,052,396; 5,076,279; 5,623,931; 5,758,650; 5,924,992; 5,928,219; and 5,941,889. Each of these devices requires that it be affixed to the transducer. Only the device described in the ""756 patent allows for independent horizontal movement of the transducer and the needle guidance portion of the apparatus. However, in the ""756 patent, the alignment of the needle with the planar ultrasound beam is dependent upon the stability of a single articulating arm. The joint of the articulating arm is connected by a single nut and bolt. Such a joint can come loose and fail to maintain proper alignment of the needle. Naturally, this can lead to problems during a medical procedure.
There is a need for an apparatus which holds and guides the needle while holding the transducer and allows for steady relative horizontal movement of the needle and the transducer.
An apparatus for guiding a needle in conjunction with an ultrasound imaging system has now been discovered which securely holds both the needle and the transducer and allows for steady relative horizontal movement between the needle and the transducer. The apparatus of the present invention provides steady movement and securely holds both the transducer and the needle guide during use by employing two parallel arms between which both the transducer and the needle guidance unit are held. These two arms while securely holding both the transducer and the needle guidance unit, allow for relative horizontal movement of the transducer and the needle guidance unit.
Additionally, the present invention employs a box-shaped frame in which the transducer is securely held. By holding rather than affixing the box-shaped frame to the transducer, the speed at which the apparatus is set up for use is greatly accelerated. The transducer is enclosed within a latex bag or other similarly made bag for sterility. Alternatively, a latex sleeve is affixed to the top of the frame such that the latex sleeve, in combination with the frame, encloses the transducer in a sterile manner.
Broadly, the present invention is a needle guidance apparatus for use with an ultrasound imaging device that generates a substantially planar ultrasound beam from one end of a transducer comprising:
(a) a box-shaped frame for securely holding a transducer when the frame with transducer therein is placed against a body of a patient;
(b) a needle guide unit having a sleeve for accommodating and guiding a needle into the body of a patient, said sleeve being coplanar with said ultrasound beam; and
(c) two parallel arms, one end of each of said arms attached to opposite sides of said frame and the other end of each of said arms attached to opposite sides of said needle guide unit, said needle guide unit pivoting around a transverse axis, said frame, or said needle guide unit, or both said frame and said needle guide unit being movable with respect to arms such that horizontal distance between said needle guide unit and said frame can be varied.
Preferably, said arms, said frame, and said transverse axis of said needle guide unit are in the same transverse plane.
In order to vary the horizontal distance between the frame and the needle guide unit, each arm has either a slit that runs lengthwise in the arm or a line of holes which also runs lengthwise in the arm. The frame, or the needle guide unit, or both the frame and the needle guide unit have releasable fasteners on their opposite sides which mate with the slot or holes and allow for relative movement.
The arms can be an extension of the frame. In such an embodiment, the needle guide unit is horizontally moveable relative to the frame as well as pivotal between said arms.
In a preferred embodiment, the opposite sides of the frame are parallel sides with outward flat surfaces which are affixed to the respective inside, flat surfaces of the arms. Having the two flat surfaces against each. other increases the overall stability and rigidity of the apparatus. Likewise, in the needle guide unit, the two opposite sides are flat parallel sides which are held flat against the inside, flat surfaces of the arms, also increasing the stability and rigidity of the apparatus.
The stability and security of the apparatus of the present invention is provided by the two arms and the orientation of the various components. The arms are oriented to be in two separate parallel vertical planes. The two vertical planes are also parallel to the plane of the ultrasound beam. The ultrasound beam is coplanar with the sleeve and, hence, the needle during insertions. Also, the axis of rotation of the needle guide unit, the two arms and the frame are, preferably, in the same transverse plane. The transverse plane forms a 90xc2x0 angle with the two vertical planes of the arms and the vertical plane of the ultrasound beam and the sleeve.
These and other aspects of the present invention may be more fully understood by reference to one or more of the following drawings and the detailed description which follows therefrom.